<template>
  <div class="xtx-carousel" @mouseenter="stop()" @mouseleave="start()">
    <ul class="carousel-body">
      <li
        class="carousel-item"
        v-for="(item, i) in slides"
        :key="item.id"
        :class="{ fade: index === i }"
      >
        <!-- 如果有imgUrl，则为图片轮播 -->
        <RouterLink to="/" v-if="item.imgUrl">
          <img :src="item.imgUrl" alt="" />
        </RouterLink>
        <!-- 如果没有，则为商品轮播 -->
        <div v-else class="slider">
          <RouterLink
            v-for="goods in item"
            :key="goods.id"
            :to="`/product/${goods.id}`"
          >
            <img :src="goods.picture" alt="" />
            <p class="name ellipsis">{{ goods.name }}</p>
            <p class="price">&yen;{{ goods.price }}</p>
          </RouterLink>
        </div>
      </li>
    </ul>
    <a href="javascript:;" class="carousel-btn prev" @click="toggle(-1)"
      ><i class="iconfont icon-angle-left"></i
    ></a>
    <a href="javascript:;" class="carousel-btn next" @click="toggle(1)"
      ><i class="iconfont icon-angle-right"></i
    ></a>
    <div class="carousel-indicator">
      <span
        @click="index = i"
        v-for="(item, i) in slides"
        :key="item.id"
        :class="{ active: index === i }"
      ></span>
    </div>
  </div>
</template>

<script>
import { ref, watch, onUnmounted } from 'vue'
export default {
  name: 'Carousel',
  props: {
    slides: {
      type: Array,
      default: () => []
    },
    // 决定是否自动轮播
    autoPlay: {
      type: Boolean,
      default: false
    },
    intervalTime: {
      type: Number,
      default: 3000
    }
  },
  setup (props) {
    const index = ref(0)
    let timer = null
    // 1、自动播放
    const autoPlayFn = () => {
      clearInterval(timer)
      timer = setInterval(() => {
        index.value < props.slides.length - 1
          ? index.value++
          : (index.value = 0)
      }, props.intervalTime)
    }
    watch(
      () => props.slides,
      (newValue) => {
        newValue.length && props.autoPlay ? autoPlayFn() : false
      },
      {
        // immediate: true,
      }
    )

    // 2、鼠标放置暂停
    const stop = () => {
      timer ? clearInterval(timer) : false
    }
    const start = () => {
      props.slides.length && props.autoPlay ? autoPlayFn() : false
    }

    // 3、点击切换
    const toggle = (i) => {
      let newIndex = index.value
      console.log(newIndex)
      switch (i) {
        case -1:
          newIndex <= 0 ? (newIndex = props.slides.length - 1) : newIndex--
          break
        case 1:
          newIndex < props.slides.length - 1 ? newIndex++ : (newIndex = 0)
          break
      }
      index.value = newIndex
    }

    // 4、销毁
    onUnmounted(() => {
      clearInterval(timer)
    })
    return {
      index,
      autoPlayFn,
      stop,
      start,
      toggle
    }
  }
}
</script>
<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;

  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }

    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;

      &.fade {
        opacity: 1;
        z-index: 1;
      }

      img {
        width: 100%;
        height: 100%;
      }
    }

    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;

      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;

        ~ span {
          margin-left: 12px;
        }

        &.active {
          background: #fff;
        }
      }
    }

    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;

      &.prev {
        left: 20px;
      }

      &.next {
        right: 20px;
      }
    }
  }

  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}

.slider {
  display: flex;
  justify-content: space-around;
  padding: 0 40px;
  > a {
    width: 240px;
    text-align: center;
    img {
      padding: 20px;
      width: 230px !important;
      height: 230px !important;
    }
    .name {
      font-size: 16px;
      color: #666;
      padding: 0 40px;
    }
    .price {
      font-size: 16px;
      color: @priceColor;
      margin-top: 15px;
    }
  }
}
</style>
